I disagree, sort of.
From a legal standpoint, the NHL needed a Kovalchuk like situation before they could have a strong enough footing to challenge one of these deals. Had they challenged the Savard deal, and lost, it would have set a powerful precedent that would have made an arbitrator far less likely to side with the NHL should they have chose to go after a following deal (such as this Kovy deal)
By working backwards though, with precedent in hand, they can look at those contracts through the lens that the arbitrators written decision provides them...and should they see sufficient grounds, based on the arb's decision to go after those contracts, they will.
A lot of where the NHL goes from here with this will be based on the written wording of the arbitrators decision. They will choose their next battle very carefully though, because if they over reach with the next shot (Savard would be an overreach at this point just based on the length and ending age imo) it will hand the PA a strong precedent to do battle with in the future.
My guess is Luongo or Hossa's deal and they'll work their way down the line one at a time if they're going to pursue this, collecting more and more precedent as they go.